ADU Types & Construction Costs: How Much Does an ADU Cost in LA?

ADUs go by many names like Accessory Dwelling Units, Auxiliary Dwelling Units, Granny Flats, Second Units, and Garage Conversions. By now you must already know that California passed AB2299 & SB1069 a few years ago to allow homeowners to build rentable units in single family neighborhoods. But do you know how much an ADU cost? Do you know what the price for an ADU is in Los Angeles?

If you are thinking of building an ADU you’ll want to read this article, it will help you understand how much you’ll spend on permit fees, architectural plans, and the total price you’ll pay to build an ADU. We will also cover the general price range for ADUs in the city of Los Angeles, Los Angeles County, and all major cities in Los Angeles County. I recently hosted an hour-long webinar about ADUs - you can access the ADU Webinar for free by clicking here

2022 Update: Supply Chain Issues & 'Texas Freeze' have caused material shortages and an increase in raw material prices. Everything from cabinets, flooring, concrete, paint, adhesives, and lumber have increased in price since 2020. Be prepared to pay 15% to 30% more for a bathroom remodel in 2021/2022. Source: Wall Street Journal

ADU Types & Uses

California’s affordable housing shortages has fueled the demand to build more housing in traditionally single-family neighborhoods. The term “Auxiliary Dwelling Unit” is the State of California’s fancy adjective for a “garage conversions” and “second units”. If you want to learn more about the law please see my blog article about ADU specifications. There are three different types of ADUs including the popular garage conversion, an Attached ADU, and a Detached ADU.

“Homeowners want to know How much does an ADU cost?”

The most common questions people ask is “How much does an ADU cost?” In construction, cost is a factor of the amount of work that is being done. If you increase the scope of work, you’ll also be increasing the price tag. These are the 3 main types of ADUs along with a brief description of the amount of work you’ll need to get it built.

1. Garage Conversion ADU (can be attached or detached) – Rehab/Remodel

2. Attached ADU (similar to an addition) – New Construction

3. Detached ADU (ground up design) – New Construction

ADU Conversion of Existing Garage: 400SF - 500 SF

A garage conversion is the cheapest of all ADU types because the framing is already existing, but it may still need some work. The cost of construction is the lowest when the garage is at the front of the lot with easy access to the sewer system. This makes this a whole lot easier. Typically in this scenario the garage ceiling will need to be reframed, you’ll need to add wall insulation, and you will need an electrical upgrade.

Required Construction Documents $15,000 - $18,500

• Architectural Floor Plans & Site Plans
• Engineering Plans (for wall, roof, and ceiling framing)
• Title 24 Report (energy calculations are required by law)
• Electrical Plan (for service panel & electrical wiring)

Construction Costs $100,000 - $120,000

If you are considering a garage conversion you can expect to pay anywhere between $15,000 to $18,500 in pre-construction expenses. All of these plans are required by your local municipality in order to get your project approved & permitted. For a good quality garage conversion, you can expect to spend anywhere between $100,000 and $120,000. This will get you a studio style ADU with a small kitchen & bath with good quality materials & finishes.

Attached ADU (New Construction) : 300 SF - 700 SF

An attached ADU is similar to a home addition because it is connected to the main structure but is a separate unit. The unit will have its own access, and depending on the city, it might also have its own address. These ADU types are a bit intrusive during construction because they often share the main sewer line and the electrical system. You’ll need to upgrade your electrical service panel to at least a 200 Amp to be able to handle the increased loads. Some municipalities require a double-meter electrical panel.

Required Construction Documents for Attached ADU $17,000 - $22,000

• Architectural Flooring and Site-Plan
• Engineering Plans (for wall, roof, and ceiling framing)
• Title 24 Report (energy calculations are required by law)
• Electrical Plan (for service panel & electrical wiring)
• Soils Report
• Property Survey

Construction Costs $180,000 - $220,000

For an attached ADU you can expect to pay anywhere between $17,000 to $22,000 in pre-construction expenses. All of these reports and plans will be required in order to get your project approved by the local zoning department. You will need a full set of plans to submit to the city for review and plan check, once approved, you can obtain a permit to begin construction.

Detached ADU (New Construction) : 350 SF - 1200 SF

Building a Detached ADU allows you to go BIG. You'll be able to design your ADU from the ground up, which means you can probably build a bigger ADU which can potentially get you higher rents (depending on your location). If your lot is large enough you can build a detached ADU up to 1,200 SF or 50% of the existing home's footprint, but this can vary depending on your municipality. A detached ADU offers all the comforts of new construction. Tenants will enjoy new insulation, air conditioning, noise-reducing double pane windows, and they'll enjoy private access to their own unit. In some cities you can even build a two-story ADU that features garaged parking on the ground floor. You can use this impressive ADU for your family, or you can rent it out to earn extra income.

Required Construction Documents for Detached ADU: $18,500 - $24,500

• Architectural Flooring and Site-Plan
• Engineering Plans (for wall, roof, and ceiling framing)
• Title 24 Report (energy calculations are required by law)
• Electrical Plan
• Survey of Lot
• Soils Report

Construction Costs $280,000 - $320,000

For an Detached ADU you can expect to spend anywhere between $280,000 to $300,000+ to build an ADU that is comfortable and luxurious. Your tenants and family alike will enjoy the modern amenities of a large detached ADU.

Want to Learn More?

• Auxiliary Dwelling Unit - What is an ADU?
• Home Addition Tips - Where to Start?
  
  

I want to thank you for visiting my website to learn about building an ADU in Los Angeles, I really hope you found my article to be helpful. If you would like to learn more about ADUs I highly recommend that you watch my recent webinar of Typical ADU Floor Plans for Los Angeles by clicking here. We discuss possible ADU floor plans for garage conversion ADUs, Attached ADUs, and Detached ADUs. You can also visit my Bay Cities Construction Blog where you can find articles about kitchen cabinets and countertops. My team has created a library of blog articles to you can be better educated about all your options when planning a second unit project. Want to speak to a Pro? Call me at (888)-881-7355 to book a complimentary consultation!